Semiconductor device and method of fabricating thereof

Abstract

A method of fabricating a semiconductor device is provided. A substrate is first provided, and than several IO devices and several core devices are formed on the substrate, wherein those IO devises include IO PMOS and IO NMOS, and those core devises include core PMOS and core NMOS. Thereafter, a buffer layer is formed on the substrate, and then the buffer layer except a surface of the IO PMOS is removed in order to reduce the negative bias temperature instability (NBTI) of the IO PMOS. Afterwards, a tensile contact etching stop layer (CESL) is formed on the IO NMOS and the core NMOS, and a compressive CESL is formed the core PMOS.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a semiconductor device and a method of fabricating thereof. More particularly, the present invention relates to a semiconductor device and fabricating method thereof capable of improving negative bias temperature instability (NBTI) of the PMOS used as a input / output (IO) device.[0003]2. Description of the Related Art[0004]In the matter of the function, the semiconductor devices can be mainly distributed into IO devices and core devices. In accordance with electrical type of the devices, the IO devices further include a IO PMOS and a IO NMOS, wherein the IO PMOS represents a PMOS used as a IO device and the IO NMOS represents a NMOS used as a IO device. The core devices similarly include a core PMOS and a core NMOS.[0005]The use of strained silicon has been utilized to improve the performance of the core device, but this manner is profitless to the reliability of a IO PMOS. Furthermore, t...

AI Technical Summary

Benefits of technology

[0006]Accordingly, a main objective of the present invention is to provide a method of fabricating a semiconductor device capable of increasing the performance and reliability of a IO PMOS through simple manufacturing steps and preventing the diffusion of hydrogen atoms into the interface between silicon (Si) and silicon dioxide (SiO2). The method has very little impact on the resistance (Rs) of the metal silicide layer.

[0007]Another main objective of the present invention is to provide a semiconductor device capable of eliminating the negative bias temperature instability (NBTI) in a IO PMOS so that the performance and the reliability of the device are improved.

[0018]In the present invention, a thin buffer layer is formed on the surface of the IO PMOS, and the buffer layer can stop the diffusion of hydrogen atoms into the interface between silicon and silicon oxide. Hence, the negative bias temperature instability (NBTI) of the IO PMOS can be eliminated or reduced without affecting the performance of other devices. Moreover, the buffer layer has very little impact on the resistance (Rs) of the underlying metal silicide layer.

Problems solved by technology

The use of strained silicon has been utilized to improve the performance of the core device, but this manner is profitless to the reliability of a IO PMOS.

Furthermore, the higher voltage is applied to the IO devices, especially the IO PMOS, so NBTI of the IO PMOS can not be reduced and thus the performance and reliability of the IO devices cannot be improved.

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